Antoinette Perrine has barricaded her front door since her brother was killed three weeks ago on a basketball court near her home in the Harlem Park neighborhood of West Baltimore. She already has iron bars outside her windows and added metal slabs on the inside to deflect the gunfire.

Perrine's brother is one of 36 people killed in Baltimore so far this month, already the highest homicide count for May since 1999. But while homicides are spiking, arrests have plunged more than 50 percent compared to last year.

The drop in arrests followed the death of Freddie Gray from injuries he suffered in police custody. Gray's death sparked protests against the police and some rioting, and led to the indictment of six officers.